Mozilla Firefox is an open source Web browser. XULRunner provides the XULRuntime environment for Mozilla Firefox.Several flaws were found in the processing of malformed web content. A webpage containing malicious content could cause Firefox to crash or,potentially, execute arbitrary code with the privileges of the user runningFirefox. (CVE-2009-3979, CVE-2009-3981, CVE-2009-3986)A flaw was found in the Firefox NT Lan Manager (NTLM) authenticationprotocol implementation. If an attacker could trick a local user that hasNTLM credentials into visiting a specially-crafted web page, they couldsend arbitrary requests, authenticated with the user's NTLM credentials, toother applications on the user's system. (CVE-2009-3983)A flaw was found in the way Firefox displayed the SSL location barindicator. An attacker could create an unencrypted web page that appears tobe encrypted, possibly tricking the user into believing they are visiting asecure page. (CVE-2009-3984)A flaw was found in the way Firefox displayed blank pages after a usernavigates to an invalid address. If a user visits an attacker-controlledweb page that results in a blank page, the attacker could inject contentinto that blank page, possibly tricking the user into believing they areviewing a legitimate page. (CVE-2009-3985)For technical details regarding these flaws, refer to the Mozilla securityadvisories for Firefox 3.0.16. You can find a link to the Mozillaadvisories in the References section of this errata.All Firefox users should upgrade to these updated packages, which containFirefox version 3.0.16, which corrects these issues. After installing theupdate, Firefox must be restarted for the changes to take effect.